No I'm sorry, removing this workaround doesn't change anything, and I'll have to try your first proposal... In the meantime I found where this comes from: I had experienced key-binding problems in Scrolled TextUndo widgets and could apply with success Zentara's tip given here Re^3: Tk hidden binding, so to be on the safe side, as my canvas is scrolled too, I just applied the same here in prevision of possible key-bindings and problems. Anyway, I must acknowledge I often copy and paste bits of code without always being sure they're appropriate, when it works no further verification is made (shame on me!).